BACKGROUND Lake Monona is the second-largest of a chain of four lakes along the Yahara River in the area and forms the south shore of the isthmus that forms downtown Madison.Lake Monona measures 3,274 acres (13.2 km²), has a mean depth of 27 ft (8 m) and a maximum depth of 64 ft (20 m). Its volume is approximately 28 billion US gallons (110,000,000 m³) and it has 13 miles (21 km) of shoreline, about 40% of which is publicly owned. The elevation of the lake is 845', regulated by locks at the mouth of the Yahara River at Lake Mendota.
Lake Waubesa is the third lake in the chain of Yahara Lakes, between Lake Monona and Lake Kegonsa. It has a total drainage area of 842 km2, and a surface area of 8.43 km2. Its total volume is approximately 40 million m3. The maximum depth is 11.6 m and the mean depth is 4.7 m.
Lake Kegonsa is the southernmost and often the windiest of the Yahara River lakes, and is surrounded primarily by agricultural land. Its watershed covers 54 square miles. Lake Kegonsa is a highly eutrophic (nutrient rich), moderatelyshallow drainage lake, formed when glacial deposits dammed the Yahara River. Much of the shore is covered by homes, with only 1.5 miles of shoreline in public ownership.

MOLTIVATION This project aims at providing wind-generated waves information of Yahara Lakes to local residents and managers for recreational use or management issues.
Group Member: Liu Liu Yan (Owen) Zhu Chaohe (Gary) Guo

In this project, SWAN is used to do build up wave models.

SWAN

(Simulating WAves Nearshore)

SWAN is development by Delft University of Technology. SWAN calculates wave energy function as a function of time, space, wave frequency and wave direction. More information is available at this address: http://www.swan.tudelft.nl/ .

Inputs

Outputs

Data For Model

Wind Data

Bathymetry Data

Lake Monona Lake Waubesa Lake Kegonsa

Firt we came up with three ideal cases to investigate our models, and to see how the wind speed and wind direction will impact the waves.

Scenario 1 (Growing time scale with a constant direction)

In this scenario, the wind direction is constant from north east, and the wind speed is constant at 8 m/s. The highest wave peek happens at downstream of the wind, and because the size of the lake is small, so it's fetch limited and the highest wave height doesn't grow too much although the wind keeps blowing.

Scenario 2 (Growing wind speed with a constant direction)

In this scenario, the wind direction is constant from north-east. Wind speed increases from 8 m/s to 17.9 m/s. As expected, when wind speed increases, the highest wave height also increases.

Scenario 3 (A constant wind speed with shifting directions)

North East

South West

In this scenario, wind blows from 4 different directions, north, east, south and west separately. We can see the highest wave height always happens downstream of the wind direction.

Historical wind data

In this case, real wind data is used and the change of wave height at three different points are shown. We can see the trend of significant wave height is not exactly the same with wind speed, this is because wind direction is also changing all the time. So significant wave height does not only depends on wind speed, also depends on wind direction.

MOLDEING WIND-GENERATED WAVES IN YAHARA LAKES

BACKGROUND

MOLTIVATION

Group Member: